Capacitive fibrillation apparatus using vacuum relays

ABSTRACT

A vacuum relay system for alternately switching a charging capacitor between a load and source of voltage. A pair of normally open contacts and a pair of normally closed contacts are provided. Actuation of a solenoid member causes an actuating rod to move in a direction which causes movement of a cross bar member. The cross bar member has an actuating bar member secured at each of its ends which moves in the same direction as the actuating rod. Movement of the actuating bar members causes a pair of normally open contacts to close and simultaneously causes a pair of normally closed contacts to open. The contacts are each individually surrounded in a vacuum environment wherein failure of the vacuum environment surrounding any of the normally open or closed contact members does not affect the vacuum environment of the other contact members.

111' 3,775,658 Nov. 27, 1973 Miles y 1 CAPACITIIVE FIBRILLATION APPARATUS usmc VACUUM RELAYS 75] Inventor: Floyd D. Miles,Saratoga,Calif.

[73] Assignee: International Telephone and Telegraph Corporation, New York,

[22] Filed: May 30, 1972 [21] Appl. No.: 258,054

[52] US. Cl. 320/1, 200/144 B, 200/153 H,

200/166 M, 335/127, 335/154, 335/185, 335/265 [51] Int. Cl H03k 3/53, H0111 47/00, H0111 3/00 [58] Field of Search 320/1; 335/127, 151, 335/154,185, 265; 200/153 1-1, 144 B 166 M [56] References Cited UNITED STATES PATENTS 3,414,898 12/1968 Barton 320/1 X 2,920,607 1/1960 Barkan 200/153 H 2,526,455 10/1950 Bonanno 200/166 M 2,441,822 5/1948 Klemperer 320/1 3,493,952 2/1970 Jette 200/144 B OTHER PUBLICATIONS G-E Metal Vacuum Switch F-6, Spec. sheet GE- T-609F, 9/2/43.

Primary ExaminerBernard Konick Assistant Examiner-Stuart l-lecker Attorney-C. Cornell Remson, Jr. et al.

571 ABSTRACT A vacuum relay system for alternately switching a charging capacitor between a load and source of voltage. A pair of normally open contacts and a pair of normally closed contacts are provided. Actuation of a solenoid member causes an actuating rod to move in a direction which causes movement of a cross bar member. The cross bar member has an actuating bar member secured at each of its ends which moves in the same direction as the actuating rod. Movement of the actuating bar members causes a pair of normally open contacts to close and simultaneously causes a pair of normally closed contacts to open. The contacts are each individually surrounded in a vacuum environment wherein failure of the vacuum environment surrounding any of the normally open or closed contact members does not affect the vacuum environment of the other contact members.

1 Claim, 7 Drawing Figures I POM/6Q I SUP/UL? CONTROL VOL T4966 PAIENIEDHMN v 3.775.658

SHEET 2 0F 2 SOLE vow CAPACITIVE FIBRILLATION APPARATUS USING VACUUM RELAYS VACUUM RELAY SYSTEM BACKGROUND OF THE INVENTION Conventional heart defibrillators are utilized to administer shock treatments to patients suffering from cardiacarrhythmia. Early types of electrical defibrillation equipment utilized sixty-cyclealternating current wavesand were found'to be effective in defibrillating an exposed heart. The need for thoracotomy and direct application of the electrodes tothe heart limited'the clinical application of the method. However, further work extended the use of the alternating current discharge defibrillator through thechest cavity and clearly defined the electrical and technical condition for defibrillation; Such techniques were referred to as transthoractic defibrillation. This technique promoted the general acceptance of alternating current countershock as an experimentaland clinical tool.

Further use of defibrillation techniques included charging a capacitor and then discharging the capacitor. This form of defibrillation was not pursued since the procedure could onlybe employed when the physician and apparatus were instantly available at the bedferent typesof direct current both during ventricular fibrillation and during the normal sinus rhythm. The effects of the countershocks were compared and it was found that DC countershock was more efficient in defibrillating the heart than AC countershock. In addition, DC countershock was found safer, as AC countershock frequently produced serious arrhythmias.

Most DC countershock has been performed by the chronizing the shock, thus avoiding the vulnerable period.

In order to overcome the attendant disadvantages of prior art relay systems which may be incorporated in heart defibrillators, thepresent invention provides redundant electrical protection. Each switch element of the relay system is enclosed in a separate vacuum element providing redundant electrical protection and eliminating the possibility of arc transfer or relay failsafe method of discharging a capacitor through an inductance. By utilizing a sixteen microfarad capacitor,

and a 100 millihenry inductance in series therewith, the waveform of the shock produced bysuch a machine is found to be relatively slow rising and underdamped. Such a shock lasts for approximately 2% to 5 milliseconds in duration. With 50 watt-seconds energy, peak tion in one-to-two percent of patients. This ventricular fibrillation may take place when'the shock occurs in the vulnerable period; that is, the ascending portion of the T-wave. This hazard can be totally avoided by synure which would result the patient being connected directly to the powersupply.

SUMMARY OF THE INVENTION The invention comprises a vacuum relay system for interconnecting a power supply between a source of 'voltage and a load. A plurality of pairs of contactmembers are provided, at least one of the contact members being normally open and another of the contact members being normally closed. Movement of an actuating rod causes the normally open contacts to close while simultaneously opening the normally closed contacts. Each of the contacts are positioned in a vacuum environment so that failure of the vacuum environmentof one of the contacts will not affect the vacuum environment of the other contacts.

' The advantages of the invention, both as to its construction and mode of operation, will be readily appreciated as the same becomes better understood by reference .to the following detailed description when consid ered in connection with the accompanying drawings in which like-referenced numerals designate like-parts throughout the figures.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1' is a schematic illustration of a system incorporatingsthe vacuum relay system and used to explain the invention;

FIG. 2 is a plan view illustrating an embodiment of the vacuum relay system;

, FIG. 3is a sectional view of the vacuum relay system of FIG. 2 taken along the lines 3-3 of FIG. 2;

FIG. 4 is a sectional view of the vacuum relay system of FIG. 3 takenalong the lines 44 of FIG. 3;

FIG. 5 is 'a sectional view of the-vacuum relay system taken along the lines 5-5 of FIG. 3; v

FIG. 6 is a sectional view of one of the normally open contacts utilized in the vacuum relay system; and

FIG. 7 is a schematic illustration of the vacuum relay system shown for purposes of explanation of the operation of the vacuum relay system.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, there is shown in FIG. 1 a schematic illustration of a system incorporating the vacuum relay system for purposes of explaining the invention. In FIG. 1, a vacuum relay system 12 is formed of a plurality of pairs of normally open contacts l4, l6 and normally closed contacts 18, 22. Each of the contacts 14, 16, 18 and 22 is mounted in vacuum sealed containers 24 of similar type construction. One side of the normally closed contacts 1'8and 22 is connected to a power supply 26 which normally comprises a DC voltage. The other side of thenormally closed contacts 18 and 22.is connected to one side of the normally open contacts'14 and 16, respectively. The other side of the contacts 14 and-16 is connected across a load which may be connected to the terminals 28, 32, In addition, the terminals common to the contacts 14 and 18 are connected to one side of a capacitor 34, the other side of the capacitor 34 being connected through a charging circuit 36 to the other side of the common connection between the contacts 16 and 22. v

, In normal operation, the normally closed contacts 18 and 22 connect the power supply 26 through the charging circuit 36 to the capacitor 34 and the capacitor 34 tends to charge toward the value of the voltage at the power supply 26L A relay 38 is utilized to close the normally open contacts 14 and 16 and simultaneously open ,the contacts 18 and 22 when actuated. When the relay 38 is actuated, the capacitor 38 will discharge through the circuit 36 and will appear across the output terminals 28, 32 and may be used to apply the voltage at the capacitor 34 across a load. By utilizing each of the switch elements 14, 16, 18 and 22 in a separate vacuum element, redundant electrical protection is provided, and the possibility of arc transfer or relay failure connecting the patient directly to the power supply is greatly reduced. Thus, redundant electrical protection is provided in theeven t of dielectric failure in one vacuum switch, in either the charging or discharging circuit. Thus, the possibility of arc transferpole-to-pole, common-to-pole, or common-to-ground is greatly reduced.

Referring now to FIGS. 2 and'3, there is shown a preferred embodiment. of the vacuum relay system. The vacuum relay system is positioned on a normally cylindrical base plate member 52, and hasvsecured thereto an electromagnetic relay assembly, or solenoid 54, by means of a conventional nut-and-bolt arrangement which is positioned on a plate 56 integrally formed with the base plate 52. An actuating rod 58 is controlled by the solenoid 54 andenergization of the solenoid 54 causes the rod 58 to move downwardly in the position shown in FIG. 3. The rod 58 is secured at one end to a plate member 62 which moves together with the rod 58 upon energization of the solenoid. The other end of the rod is threadably secured to a cross bar member 64. The cross bar member 64 has at each end secured thereto a pair of actuating bar members 66 and 68. The central portion of the bar members have bowed portions 69 and 70, respectively, shown more clearly in FIGS. 4 and 7, which can be bent to allow for lengthening or shortening of the bars 66 and 68, thus allowing adjustment of the contact mechanism.

Each of the members 66 and 68 has secured at their corners one end of an armature member 72, 74, 76 and 78, respectively. As can be seen in FIG. 6, a typical armature member mounted in a contact is shown. The armature member 72 extends through one end of a flexible diaphragm member 74 and terminates at the other end of a switching housing 92 in an electrical contact 94. The housing 92 is formed of a cylindrical wall member 96 which is made of insulator material. A conductive bottom plate 102 has secured, between the wall member 92 and the plate 102, a flange 104 which is made of conductive metal and which extends inwardly in a cylindrical portion 106 so as to form a contacting surface associated with the contact 94. Pivotal move- I ment of the armature 72, as shown by the arrows in FIG. 6, will cause the contact surface 94 to electrically connect with the member 106 or disconnect therefrom, as the case may be. In addition, the bottom plate 102 has a central opening 108, through which a terminal member 1 12 is secured. The terminal member forms an electrical connection by means of a cap 114. Thus, when the contact 94 abuts the surface of portion 106, a through electrical connection is made between the armature 72 and the terminal cap 114.

Referring now to FIG. 7, there is shown a schematic illustration for purposes of explaining the operation of the vacuum relay system. The solenoid 38 is utilized to move the actuating rod 58, thus causing cross bar member 64 to move forward. Forward movement of the cross bar member 64, in turn, causes the actuating bar members 66 and 68 to also move forward which, in turn, causes the normally open contacts associated with armatures 72 and 76 to close ,while simultaneously opening the normally closed contact associated with armatures 74 and 78.

In addition, it should be understood that other variations of the normally open and closed contacts are possible. For example, the end of the actuating bar members could have one normally open and one normally closed contact associated therewith. Moreover, more or less than four contacts could be used with the relay system as well as more or less actuating bar members and associated contacts. g

It should be further understood that the foregoing disclosure relates only to preferred embodiments of the invention, and that it is intended to cover all changes and modifications of the examples of the invention herein chosen for the purpose of the disclosure which do not constitute departures from the spirit and scope of the invention.

What is claimed is:

1. Apparatus for use in alleviating the fibrillation of a patients heart, said apparatus comprising: support means; first and second pairs of switches, said first pair including first and third switches, said second pair including second and fourth switches, each of said switches being a single-pole, single-throw switch, each switch having an evacuated envelope and first and second contacts mounted therein, at least said first contact of each switch being movable repeatedlyinto and out of electrical contact with said second contact thereof without breaking the vacuum, each switch having first and second external conductors for electrical connection to an electrical circuit, said first and second conductors for each switch having respective first and second portions extending through the wall of the corresponding envelope thereof into electrical contact with and fixed relative to said first and second contacts, respectively, said first and second conductors of each switch being mounted on the corresponding envelope thereof in positions insulated from each other except when the corresponding contacts thereof are moved into electrical contact with each other as aforesaid, said switches all being ganged; selectively operable means mounted on said support means to move all of said first conductors simultaneously from respective first positions in which said first and second switches are open and said third and fourth switches are closed to respective second positions in which said first and second switches are closed and said third and fourth switches are open, and vice versa; a DC. power supply having firstand second leads and an output voltage appearing, between said leads thereof; a capacitor; a charging circuit; first and second auxiliary leads; and first and second terminals for connectionwith spaced areas on the human body, said first switch being connected from said first auxiliary lead to said first terminal, said second switch being connected from said second auxiliary lead to said second terminal, said third switch being connected from said power supply first lead to said first auxiliary lead, said fourth switch being connected from said power supply second lead to said second auxiliary said respective first positions thereof and the other of said first and second switches loses vacuum, said power supply output voltage being insulated from said second terminal by either one of said third and fourth switches so long as it has not lost vacuum when said first conductors are in said respective second positions thereof and the other of said third and fourth switches loses vacuum, at least one of said terminals always being insulated from said power supply by one of the switches of one of said switch pairs when both of the switches of the said one pair have not lost vacuum even though none, only one or both of the switches of the other pair have lost vacuum. 

1. Apparatus for use in alleviating the fibrillation of a patient''s heart, said apparatus comprising: support means; first and second pairs of switches, said first pair including first and third switches, said second pair including second and fourth switches, each of said switches being a single-pole, single-throw switch, each switch having an evacuated envelope and first and second contacts mounted therein, at least said first contact of each switch being movable repeatedly into and out of electrical contact with said second contact thereof without breaking the vacuum, each switch having first and second external conductors for electrical connection to an electrical circuit, said first and second conductors for each switch having respective first and second portions extending through the wall of the corresponding envelope thereof into electrical contact with and fixed relative to said first and second contacts, respectively, said first and second conductors of each switch being mounted on the corresponding envelope thereof in positions insulated from each other except when the corresponding contacts thereof are moved into electrical contact with each other as aforesaid, said switches all being ganged; selectively operable means mounted on said support means to move all of said first conductors simultaneously from respective first positions in which said first and second switches are open and said third and fourth switches are closed to respective second positions in which said first and second switches are closed and said third and fourth switches are open, and vice versa; a D.C. power supply having first and second leads and an output voltage appearing between said leads thereof; a capacitor; a charging circuit; first and second auxiliary leads; and first and second terminals for connection with spaced areas on the human body, said first switch being connected from said first auxiliary lead to said first terminal, said second switch being connected from said second auxiliary lead to said second terminal, said third switch being connected from said power supply first lead to said first auxiliary lead, said fourth switch being connected from said power supply second lead to said second auxiliary lead, said capacitor and said charging circuit being connected in series from said first auxiliary lead to said second auxiliary lead, all of said switches being constructed to withstand said power supply output voltage, loss of vacuum in any one of said switches, when open, thereby causing it to conduct, said power supply output voltage being insulated from said first terminal by either one of said first and second switches so long as it has not lost vacuum when said first conductors are in said respective first positions thereof and the otHer of said first and second switches loses vacuum, said power supply output voltage being insulated from said second terminal by either one of said third and fourth switches so long as it has not lost vacuum when said first conductors are in said respective second positions thereof and the other of said third and fourth switches loses vacuum, at least one of said terminals always being insulated from said power supply by one of the switches of one of said switch pairs when both of the switches of the said one pair have not lost vacuum even though none, only one or both of the switches of the other pair have lost vacuum. 